Idle fluctuates on Ford and trouble codes P0505 or P0506

Ford has issued a service bulletin #12-7-4 to address a P0505, P0506, Idle fluctuation problem on the vehicles listed below. The problem may exhibit P0505, P0506, with or without idle fluctuation and hard starts. In addition, the vehicles may also have P2111 and P2112 codes stored after the keep alive memory has been cleared, battery has been disconnected, or the vehicle had a dead battery.

Ford has determined that the problem is caused by carbon buildup in the electronic throttle body

The REPAIR involves updating the PCM with the latest calibration and cleaning the electronic throttle body. To clean the throttle body, follow these steps:

1) Remove the throttle body from the intake manifold
2) Use Motorcraft Choke and Linkage Cleaner (PM-14) to spray the throttle body plate and bore.
3) Use a soft clean solvent resistant brush to clean the edges of the throttle plate and throttle bore to remove carbon deposits.

Clean throttle plate

NOTE: Do NOT spray the cleaner directly into the throttle plate pivot shaft. The cleaner can enter the motor area and cause damage.
4) Wipe clean and reinstall the throttle body

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